In order to test whether the mean IQ of employees in an organization is greater than 100, a sample of 30 employees is taken and the sample value of the computed test statistic, t_n-1=3.4. The null and alternative hypothesis are:（）

A. H₀: μ=100; H_a: μ≠100.

B. H₀: μ≤100; H_a: μ＞100.

C. H₀: X=100; H_a: X≠100.

保险利益必须是已经确定或者可以确定的利益，不包括______。

A．现有利益
B．期待利益
C．或有利益
D．投保人或者被保险人对已经拥有财产的所有权、占有权、使用权等而享有的利益